Get role of a User in a certain group

gistfile1.php

<?php
$c = $modx->newQuery('modUserGroupRole');
$c->innerJoin('modUserGroupMember','UserGroupMembers');
$c->innerJoin('modUserGroup','UserGroup','UserGroup.id = UserGroupMembers.user_group');
$c->where(array(
   'UserGroupMembers.member' => $userId,
   'UserGroup.name' => $userGroupName,
));
$role = $modx->getObject('modUserGroupRole',$c);

return $role ? $role->get('name') : '';